Genome resource banking for wildlife conservation: promises and caveats

The value of cryopreserved germplasm in agriculture, aquaculture and medicine was recognized in the mid-twentieth century following the discovery in the late 1940s of a method for recovering viable spermatozoa after freeze-thawing. Sir Alan Parkes (a founder of cryobiology as a discipline) remarked that "time and space has been abolished for cattle breeding", a phrase that continues to summarise the potential value of the Genetic Resource Bank (GRB) concept for all species. The underlying principle behind these remarks was based on the recognition that spermatozoa could remain viable for many years, and still achieve pregnancies even long after the semen donor had died. Nowadays, live mammalian embryos, amphibian spermatozoa and cultured somatic cells can also be stored for future use in conservation breeding programmes, where the overarching aim is to mitigate the deleterious impacts of inbreeding on the fitness and survival of populations. Revolutionary advances in the cryobiology of coral spermatozoa, embryos and larvae are also helping to counter the damaging effects of climate change and toxic chemicals on coral reefs. In this article we review the ways in which GRBs can contribute to global conservation activities, noting that species-specific biological differences can limit the success of standard animal breeding technologies such as artificial insemination and embryo transfer. These limitations mean that there is still a need for the development of novel, and possibly species-specific, GRB technologies.